Intraoperatively adjusting guide alignment

ABSTRACT

An alignment guide includes a main body sized and shaped to contact the proximal end of a tibia, and a retaining guide coupled to the main body. The retaining guide includes guide surfaces and is adjustable relative to the main body such that an operator can intra-operatively adjust the position of the guide surfaces relative to the main body to capture the anterior and posterior cruciate ligament between the guide surfaces.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the full benefit of United States Provisional Application Ser. No. 61/681,487, filed Aug. 9, 2012, and titled “INTRAOPERATIVELY ADJUSTING GUIDE ALIGNMENT”, the entire contents of which are incorporated herein by reference.

BACKGROUND

Cutting guides are used during orthopaedic procedures to insert pins in hone and guide resections to the bone to prepare the bone for receipt of an implant. For example, during bi-cruciate retaining total knee arthroplasty, a cutting guide used to prepare the proximal end of a patient's tibia is designed the leave intact portions of the tibial eminence that function as attachment sites for the anterior and posterior cruciate ligaments.

SUMMARY

A cutting guide for preparing the proximal end of a patient's tibia is described in International Application WO 2012/051542, titled Patient-Matched Instrumentation and Methods, hereby incorporated by reference in its entirety. Prior to placing the cutting guide on the bone, an alignment guide can be used to preposition alignment pins over which the cutting guide is subsequently placed to guide bone resections.

An alignment guide can include a ligament retaining guide that is adjustably mounted to a main body of the cutting guide to allow the operator to intra-operatively adjust the position of the retaining guide. Adjusting the retaining guide aligns, for example, pin receiving holes of the retaining guide through which the alignment pins are placed in the bone.

In a particular example, the alignment guide is configured to mount to the proximal end of a patient's tibia. The alignment guide has a bone mount, for example, a portion of the alignment guide that defines the pin receiving holes, and a pair of horizontal rods spaced to capture the anterior and posterior cruciate ligaments therebetween that are used to visualize subsequent eminence resections.

According to one aspect, an alignment guide includes a main body sized and shaped to contact the proximal end of a tibia, and a retaining guide coupled to the main body. The retaining guide includes guide surfaces and is adjustable relative to the main body such that an operator can intra-operatively adjust the position of the guide surfaces relative to the main body to capture the anterior and posterior cruciate ligament between the guide surfaces.

Embodiments of this aspect may include one or more of the following features.

The retaining guide is coupled to the main body such that the position of the retaining guide is rotationally and linearly adjustable relative to the main body. The retaining guide includes a bone mount that defines through holes. The main body includes a horseshoe shaped upper portion having surfaces for contacting the proximal surface of the tibia, and a lower portion having surfaces for contacting the anterior face of the proximal end of the tibia. The bone contacting surfaces of the main body comprise patient-matched surfaces. The main body defines a slot.

The main body defines a through hole that receives the retaining guide, and the retaining guide includes a shaft received in the through hole with the shaft being rotatable relative to the main body. The retaining guide includes a bone mount coupled to the shaft for linear motion relative to the shaft.

According to another aspect, a method includes positioning an alignment guide on the proximal tibia, the alignment guide including a main body and a retaining guide; and intra-operatively adjusting the position of the retaining guide relative to the main body to capture the anterior and posterior cruciate ligament.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an alignment guide.

FIG. 2 is another perspective view of the alignment guide.

FIG. 3 is a perspective view of a main body of the alignment guide.

FIG. 4 is a perspective view of a cruciate retaining guide of the alignment guide.

FIG. 5 illustrates a tibia after plateau and eminence resections have been made.

DETAILED DESCRIPTION

Referring to FIG. 1, an alignment guide 10 for placing pins for use in aligning a cutting guide that prepares a proximal tibia for receipt of an implant during bi-cruciate retaining total knee arthroplasty includes a main body 12 and a cruciate retaining guide 14. The retaining guide 14 can rotate, arrow 16, and translate, arrow 18, relative to the main body 12 to provide intraoperative adjustability of the position of the retaining guide 14 relative to the main body 12.

Referring also to FIG. 2, the main body 12 includes a horseshoe shaped upper portion 20 having surfaces 22, 24 for contacting the proximal surface of the tibia, and a lower portion 26 having a medial surface 28 for contacting the anterior face of the proximal end of the tibia. The bone contacting surfaces 22, 24, 28 of the main body are, for example, patient-matched surfaces. The lower portion 26 can also include a lateral surface or have a lateral surface rather than the medial surface 28.

The lower portion 26 defines a slot 30 through which alignment pins (not shown) are placed into the bone. The upper portion 20 defines through holes 38, 40 and the lower portion 26 defines through holes 46 for receiving fixation pins (not shown) used to fix the main body 12 to the tibia. On the anterior side of the upper portion 20 is a retaining guide mount 32 defining a through hole 42 (FIG. 3) that receives the retaining guide 14. The superior side of the upper portion 20 defines two slots 44 that function as indicia to aid in aligning the retaining guide 14 relative to the main body 12.

Referring to FIG. 4, the retaining guide 14 includes two horizontal rods 50, 52 connected by a cross bar 54, a bone mount 58 connected to the cross bar 54 by two vertical bars 66, 68, and a shaft 56 that extends between the cross bar 54 and the bone mount 58. At each end the shaft 56 terminates in a rectangular block 62. One of the blocks 62 is received within a slot 64 defined by bone mount 58 and the other block 62 is received within a corresponding slot (not shown) defined by the cross bar 54. The blocks 62 can slide within the slots 64 to provide the translation along arrow 18. The shaft 56 can rotate about its longitudinal axis, Y, within the through hole 42 of the retaining guide mount 32.

The retaining guide rods 50, 52 each have inner guide surfaces 70, 72, respectively, used to visualize the alignment of subsequent eminence resections. The retaining guide 14 is coupled to the main body 12 via through hole 42 and shaft 56 such that in use the guide rods 50, 52 are positioned to capture the cruciate ligaments therebetween. By aligning the guide rods 50, 52 with the indicia slots 44, the operator positions the retaining guide 14 to achieve best fit and coverage of a presumed implant. The operator can deviate from this alignment by adjusting the position of the retaining guide 14. The operator may decide to deviate from alignment with the indicia slots 44 for the sake of aligning the eminence resections with the femur or a femoral trial in extension and/or flexion. To allow the patient's leg to be placed in extension with the alignment guide 10 on the tibia, medial and lateral sections of the upper portion 20 of the main body 12 are made excisable from the remainder of the main body by, for example, including perforations or webs in the upper portion.

The bone mount 58 defines two through holes 90, 92, each for receiving an alignment pin. The relative position of the holes 90, 92 and the guide surfaces 70, 72 correspond to the relative position of pin receiving holes and cutting guide surfaces on a cutting block, for example, a patient matched cutting block. Referring also to FIG. 5, due to the corresponding relative positions, when the alignment pins placed through holes 90, 92 are subsequently used to place the cutting block, the alignment pins are positioned at the intersection of subsequent horizontal plateau resections 310, 320 and vertical eminence resections 340, 350 made using the cutting guide, creating curved sections 370 at the intersections.

In use, after the main body 12 is fixed to the proximal end of the tibia using pins placed through holes 38, 40, and 46, the operator intra-operatively adjusts the position of the retaining guide 14 relative to the main body 12 about arrow 16 and along arrow 18 to adjust the position of the guide surfaces 70, 72 relative to the main body 12. Fixing the main body 12 to the tibia fixes three degrees of freedom of movement of the retaining guide 14. Rotation about arrow 16 and sliding along arrow 18 permits adjustment of an additional two degrees of freedom of movement of the retaining guide 14.

When the operator determines that the guide surfaces 70, 72, and thus the resulting vertical eminence resections 340, 350, are adequately spaced from the attachment sites of the cruciate ligaments, the operator places the alignment pins through holes 90, 92. The operator then removes the alignment guide 10 leaving the alignment pins in place in the bone, and places a cutting block over the alignment pins. The cutting block can include patient-matched bone contacting surfaces that correspond to bone contacting surfaces 22, 24, 28 of the main body 12. The discrete bone contacting surfaces allow some adjustability in the placement of the patient-matched cutting block to allow the cutting block to be aligned with the alignment pins.

The main body of a patient-matched alignment guide can be created from a MRI scan and X-rays, or other imaging modalities such as CT. The main body can be made of nylon on a rapid prototyping machine or other plastics, ceramics, or metals can be used. The main body can be machined. The main body can have a different geometry and touch different parts of the anatomy. The retaining guide is made, for example, from metal and can be reusable or disposable.

Other embodiments are within the scope of the following claims.

For example, the retaining guide can be locked in a desired position. Continuous planar adjustment between the main body and the retaining guide (combined medial-lateral and internal-external) can be provided by a planar joint that has plane-to-plane contact rather than a sliding/rotating joint. The retaining guide can be configured to be moved inferior-superior in addition to medial-lateral and internal-external to enable the retaining guide to be moved closer to the eminence. Alternatively, part of the upper portion of the main body can be removable once the alignment guide 10 is pinned to the tibia so that the retaining guide has room to drop down closer to the eminence.

In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained.

The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents. 

1-9. (canceled)
 10. A method comprising: positioning an alignment guide on a proximal tibia, the alignment guide including a main body and a retaining guide; and intraoperatively adjusting the position of the retaining guide relative to the main body to capture the anterior and posterior cruciate ligament. 